How do you combine like terms in -5( - 1- 4m ) - 8m ( - 8m + 5)?

Mar 2, 2018

The asnwer is $64 {m}^{2} - 20 m + 5$

Explanation:

Multiply the terms outside the brackets by each of the terms inside the first brackets:

$\left(- 5\right) \cdot \left(- 1\right) + \left(- 5\right) \cdot \left(- 4 m\right)$

$= 5 + 20 m$

Do the same with the second brackets:

$\left(- 8 m\right) \left(- 8 m\right) + \left(- 8 m\right) \left(+ 5\right)$

$= 64 {m}^{2} - 40 m$

$64 {m}^{2} - 40 m + 5 + 20 m$
$= 64 {m}^{2} - 40 m + 20 m + 5$
$= 64 {m}^{2} - 20 m + 5$